The present invention relates generally to a mechanism for adjusting the height of a backrest relative to the chair seat, and more particularly, to a rack and pawl mechanism that will facilitate the assembly of the chair at the user's cite after being shipped in a knock down condition.
An assembled chair requires a large shipping carton which augments the shipping cost. For this reason it is advantageous and economical to ship products such as chairs in a partially assembled or "knocked down" condition. Another advantage of shipping products such as chairs in the "knocked down" condition is that the individual components can be packaged such that the likelihood of damage during shipment is reduced as compared to shipping the fully assembled chair. However, when a product is shipped in the "knocked down" condition, the final assembly becomes the responsibility of the consumer. For this reason it becomes important that products that are to be shipped in the "knocked down" condition be designed and built for easy final assembly by the consumer.
The position of a chair's backrest relative to the chair seat is an important consideration in the comfort of the user. Thus, providing an adjusting mechanism that is easy and convenient for the user is important. An operator can locate the most appropriate location for the backrest if the adjustment is made while the user is seated in the chair. It is also important that the backrest can be adjusted in small increments in order to obtain the most suitable location. Since some users of chairs desire to adjust the backrest to accommodate the particular task that they are performing or to adjust to different locations to provide a variety of seating posture, it is important that the backrest can be easily and quickly adjusted.
For the foregoing reasons, there is a need for an adjustable backrest for a chair that can be inexpensively produced, conveniently and easily assembled after being shipped in the "knocked down" condition, and is simple and handy to readjust after final assembly.